Though many physicians warn their patients about consuming too much cholesterol, everyone needs a certain amount of the right forms. Cholesterol helps produce hormones, contributes to development of the brain, and aids the functioning of the nervous system. It is not necessary to consume high levels of cholesterol in foods because the liver manufactures all that the body needs.
Because cholesterol is insoluble in water and because it cannot mix with the blood, it is carried through the bloodstream in protein "packets" called lipoproteins. The two most common kinds of lipoproteins are low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Blood cholesterol consists largely of LDL and HDL, although there are several other types of blood fats, including very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), and triglycerides.
Most of the cholesterol typically circulating in the bloodstream is carried by LDL. LDL is often called "bad" cholesterol because extra LDL cholesterol that is not used by the body tends to collect on the lining of the blood vessels and can cause arteriosclerosis (build up of fatty deposits, or plaque, in the arteries). Arteriosclerosis can reduce the supply of blood carrying oxygen and other vital nutrients to the heart and other organs and cause several heart disorders. Blood clots (thrombosis) that form around cholesterol deposits can also clog the arteries supplying the brain with oxygen and cause brain damage as well as strokes.
HDL cholesterol usually is called "good" cholesterol because it can be eliminated by the body more easily. HDL cholesterol also appears to help prevent the formation of fatty plaques in the arteries, and thus may help protect against heart disease.
Cholesterol is highly concentrated in egg yolks and organ meats such as liver, and is also found in milk, dairy products, poultry, and seafood. Only animal products contain cholesterol, although prepared foods, including crackers or bakery goods, also contain high-cholesterol ingredients such as lard, eggs, or butter.
Many people find it difficult to determine whether they eat foods which contain too much cholesterol, especially "bad" cholesterol. Part of the problem is that many foods which are high in cholesterol are also high in saturated fat–meat, butter, cheese, whole milk, cream, and ice cream, for example. It is not clear whether cholesterol alone, especially "bad" cholesterol, is harmful, but it is clear that a diet high in LDL and saturated fats should be avoided.
Blood tests are the only means of determining whether a person's cholesterol is too high. If cholesterol numbers are borderline, a cholesterol-lowering diet along with a yearly check-up is likely to be prescribed. The doctor may also recommend other lifestyle changes like exercising, quitting smoking, and limiting alcohol and coffee consumption. If the LDL ratio is unusually high, some physicians may prescribe cholesterol-lowering drugs to bring blood lipids down to normal levels.
A Few Health Facts
- Frequency of heart attacks in the U.S.: every 25 seconds.
- Frequency of fatal heart attacks in the U.S.: every 45 seconds.
- Average American male's risk of death from heart attack: 50%.
- Average vegetarian American male's risk of death from heart attack: 4%.
- Reduction of heart attack risk by eliminating consumption of meat, dairy products, and eggs: 90%.
- Rise in blood cholesterol from consuming one egg per day: 12%.
- Rise in heart attack risk from a 12% rise in blood cholesterol: 24%.
